The suspect who police believe gunned down two firefighters Sunday after starting a brush fire in Idaho wanted to pursue a career as a firefighter himself, his grandfather told CNN.

New details are emerging about the 20-year-old suspect that police say started a brush fire and then began shooting at firefighters responding to it in an ambush-style attack. Police say he has no criminal record and likely used a shotgun before dying from a self-inflicted wound six hours after the shooting began.

The suspect who allegedly ambushed firefighters on the job in Coeur d'Alene, Idaho, had contact and discussion with first responders before shooting at them with a shotgun, killing two of them and critically injuring a third,